TW201328972A - Segmented graphene nanoribbons - Google Patents

Abstract

The present invention relates to a segmented graphene nanoribbon, comprising at least two different graphene segments covalently linked to each other, each graphene segment having a monodisperse segment width, wherein the segment width of at least one of said graphene segments is 4 nm or less.

Description

Segmented graphene nanobelt

The present invention relates to a segmented graphene nanobelt and a method for making the graphene nanobelt.

Graphene, which is a thin layer of atomic graphite, has received extensive attention in physics, materials science, and chemistry because it has recently been found to have attractive electronic properties. Such characteristics relate to preferred electron mobility of the charge carriers and the quantum Hall effect (quantum Hall effect). In addition, its chemical robustness and material strength make graphene an ideal candidate for applications from transparent conductive electrodes to devices used in charge and energy storage applications.

The graphene nanobelt (GNR) is a linear structure derived from the parent graphene lattice. It is characterized by high shape anisotropy due to an increase in length to width ratio. At present, the field of materials science is widely discussed and applied to smaller, flatter and faster carbon-based devices and integrated circuits. Compared to graphene, the armchair type GNR exhibits an electron band gap that is strongly related to its width. At the same time, the edge structure of the GNR has a strong influence on the electronic characteristics. The computational simulations and experimental results on the smaller nanographene indicate that the GNR exhibiting an unbonded π-electron state at the zigzag edge can be used as an active component in a spin sub-device.

Graphene nanoribbons (GNR) are high-progress building blocks for novel graphene-based electronic devices. In addition to the difference between the most important conductive zigzag edge (ZGNR) and the predominantly semiconducting armchair edge band (AGNR), the more general GNR geometry differences allow for one-dimensional (1D) quantities. The sub-limit performs the tuning of the gap. In general, increasing the tape width results in a reduction in the band gap as a whole, and its superimposed oscillation characteristics can be maximized in the case of an armchair type GNR (AGNR).

At this point, the inner GNR heterostructure can provide a completely new concept for the implementation of (optical-) electronic devices. Indeed, the use of GNRs rather than crystalline semiconductor films as building blocks allows for full utilization of the quantum properties of the components and potentially provides an interface between different GNRs without defects. The tuning of the bandgap between different components of a heterojunction can be achieved simply by varying the width of the component rather than changing its chemical composition, potentially allowing "all carbon" device components. A number of electronic components for use in integrated circuits and other devices made of GNR heterojunctions are described, for example, in patent application US 2009/0174435.

However, standard top-down manufacturing techniques, such as graphene sections (eg, using lithography), unwinding carbon nanotubes (as described in US 2010/0047154 and US 2011/0097258), or using nanometers The template of the line (as described in KR 2011/005436) does not apply to strips narrower than 5 to 10 nm because of the lack of precise control of the edge configuration and the inability to produce strips having a monodisperse width distribution. In the case of high-efficiency electronic devices, the width of the tape must be much less than 10 nm, the width of which needs to be precisely controlled, and the important system, the edges of which must be smooth, because even slight deviations from the ideal edge shape can cause severe deterioration of electronic properties.

The strong interest in heterojunctions and heterostructures (combinations of multiple heterojunctions) stems from the fact that they are the basic building blocks of contemporary high-speed optical electronics. Semiconductor heterostructures typically exhibit different electron band gaps by stacking Crystalline materials are fabricated in which molecular beam epitaxy or chemical vapor deposition techniques are required to precisely control the 2D interface. Side heterojunctions represent even more difficult challenges. Polycrystalline graphene can utilize the (intrinsic side) grain boundaries to act as a 1D interface, and the orientation of the confinement domain boundaries may be related to electron and transport properties. The controllable "0D" heterojunction from the 1D interface to the structure consisting of finite atomic groups thus shows a highly attractive next step.

However, due to the inherent limitations of lithography and other known methods of fabricating graphene nanostructures, it is still difficult to experimentally achieve a GNR heterojunction with the desired high precision. Currently based on dehydrocyclization in solution (for example, Dössel, L.; Gherghel, L.; Feng, X.; Müllen, K. Angew. Chem. Int. Ed. 50, 2540-2543 (2011)) or solid The bottom-up method of the substrate (e.g., Cai, J.; et al. Nature 466, 470-473 (2010)) shows a high promising pathway for the synthesis of nanobelts and nanographenes with precise control of the edge structure.

In the case of a solution-based process using an oligophenylene precursor, the polymer is typically produced in a first step which is subsequently converted to a graphite structure by Scholl-type oxidative dehydrocyclization. However, the design of the parent monomer must be carefully adjusted to ensure that the aromatic unit achieves a suitable configuration when chemically assisted graphitization into the final GNR structure.

J. Wu, L. Gherghel, D. Watson, J. Li, Z. Wang, CDSimpson, U. Kolb, and K. Müllen, in Macromolecules 2003, 36, 7072-7089, reported by intramolecular oxidative dehydrocyclization By repeating the Diels-Alder cycloaddition of 1,4-bis(2,4,5-triphenylcyclopentadienone-3-yl)benzene with diacetylenyltriphenyl ( Diels-Alder cycloaddition) The obtained soluble branched polyphenylene is synthesized to realize the synthesis of the graphite nanobelt. The resulting graphene band is not linear but encompasses the statistical distribution "knot" attributed to the structural design of the polyphenylene precursor.

Y. Fogel, L. Zhi, A. Rouhanipour, D. Andrienko, HJ Räder, and K. Müllen, Macromolecules 2009, 42, 6878-6884, reporting the use of a rigid dibenzopyrene nucleus in a repeating unit by microwave assisted Dil The s- alder reaction synthesizes five monodisperse band type polyphenylene homologs. In the aromatic backbone of up to six dibenzoindole units, the resulting polyphenylene bands range in size from 132 to 372 carbon atoms. Because of the flexibility of the backbone and the substitution by the periphery of the dodecyl chain, the polyphenylene strip is soluble in organic solvents. In another reaction step, a polycyclic aromatic hydrocarbon (PAH) is obtained by dehydrocyclization.

All of these solution-based methods result in non-segmented graphene nanoribbons and the dehydrocyclization step cannot be controlled in such a way as to produce a segmented band. In addition, all of these processes will produce very insoluble GNR products that irreversibly condense in solution and cannot be treated in individual graphene bands but in graphite carbon.

The surface-restricted bottom-up method of controlled graphene nanoribbons has been described in J. Cai et al., Nature 466, pp. 470-473 (2010). However, the segmented GNR structure has not yet been obtained.

It is an object of the present invention to provide a graphene nanobelt (GNR) having precise control of edge configuration and a well defined width, which can be used to form a heterojunction, and to provide a method for making such a graphene nanobelt .

According to a first aspect, the present invention provides a segmented graphene nanoribbon comprising at least two different graphene segments covalently bonded to each other, each graphene segment having a monodisperse fragment width, wherein At least one of the graphene fragments has a fragment width of 4 nm or less.

Fragment width was determined using a scanning tunneling microscope (STM). The finite end radius is obtained according to the STM simulation corrected apparent width as described in J. Cai et al., Nature 466, pages 470 to 473 (2010). The STM images were simulated using the additional ball algorithm according to the Tersoff-Hamann method, including the effect of the end on the apparent band width. The Gaussian and plane wave methods are used to determine the integrated density of the energy states between Fermi energy and Fermi energy plus a given sample deviation for a particular geometry.

In the example of a bottom-up synthesis method employed in the present invention and as will be discussed in more detail below, the structure of the repeating unit may be in particular (i.e., the source of the repeating unit) The structure of the bulk compound) and the degree of dehydrocyclization are adjusted for fragment width, which can be measured using a scanning tunneling microscope. In principle, the segment width can be calculated directly based on this information base.

Similar to conventional polymers, each segment of the segmented graphene nanoribbon has its specific repeating unit. The term "repeating unit" refers to a portion of a fragment that will be repeated such that the repeating units are linked together in succession to obtain a full fragment (except for both ends). Different neighbor segments have different repeating units.

The term "monodisperse fragment width" means that the fragment has a length greater than its length. Constant width, if measured via STM, the standard deviation is less than 0.30 nm, more preferably less than 0.15 nm, or even less than 0.10 nm.

Preferably, each graphene segment of the segmented graphene nanoribbon has a monodisperse fragment width of 4 nm or less, more preferably 3 nm or less, and still more preferably 2 nm or less.

As will be described in more detail below, preferably, the different neighbor graphene segments are different in terms of their monodisperse fragment width. However, in the present invention, it is also possible to have two or more segments of the adjacent graphene fragments having equal monodisperse fragment widths, but at least one other property is different.

Preferably, each graphene fragment has a compound derived from at least one substituted or unsubstituted polycyclic aromatic monomer compound, more preferably at least one substituted or unsubstituted polycyclic aromatic hydrocarbon monomer, and/or derived from a repeating unit of at least one substituted or unsubstituted oligophenylene hydrocarbon monomer compound.

Polymerization of at least one substituted or unsubstituted polycyclic aromatic monomer compound and/or at least one substituted or unsubstituted phenylene aromatic hydrocarbon monomer compound, as will be described in more detail below. Each graphene fragment was obtained. The substituted or unsubstituted polycyclic aromatic monomer compound derived from the repeating unit of the fragment includes, for example, naphthalene, anthracene, naphthacene, pentacene, hexacene, naphthacene, octaphenyl, pentacene , phenanthene, bisanthene, trisanthene, fused naphthalene, anthracene, extended triphenyl, benzo[ a ]pyrene, anthracene, anthracene, etc., all of which may be substituted or unsubstituted . Substituted or unsubstituted oligophenylene hydrocarbon monomer compounds derived from the repeating unit of the fragment include, for example, biphenyl, terphenyl, terphenyl, pentacene, hexaphenyl, hexaphenyl, hydrazine Octabenzene, which may be substituted or unsubstituted.

The fragment width of the graphene fragment can also be expressed as the number of cyclic aromatic rings across the width of the fragment of the graphene fragment repeating unit. Preferably, the repeating unit of the graphene fragment has a cyclic aromatic ring of 17 or less, more preferably 8 or less across the segment width. With respect to the preferred lower limit, preferably, the repeating unit of the graphene fragment has at least 2 or at least 3 cyclic aromatic rings across the width of the segment.

The graphene fragments may also be bonded to at least one oligophenyl-derived fragment that does not comprise a cyclic aromatic ring across the width of the fragment.

Alternatively, according to conventional concepts, the fragment width of an armchair-type graphene fragment can also be expressed as the number of dimeric lines or pairs of carbon atoms across the width of the fragment (K. Wakabayashi et al., Sci. Technol. Adv. Mater. 11 (2010) 054504). By way of example only, a full-ring (ie, fully dehydrocyclized) non-segmented graphene nanoribbon having a pentacene-based repeating unit will have a dimer line with a fragment width of N=11. .

The repeating unit of the different graphene fragments may have a dimer line having a cross-fragment width of N of from 3 to 38, more preferably from 3 to 21 or from 5 to 20.

As outlined above, the segmented graphene nanobelt comprises at least two distinct segments of graphite, which means that at least two segments of the graphene segment exhibit differences on their repeating units.

Preferably, the repeating unit of the different graphene fragments is at least selected from the group consisting of a fragment width, a substituent attached to the repeating unit, a degree of aromatic ring ring formation or a degree of dehydrocyclization, and/or a number of cyclic aromatic rings. One or more displays differently.

The degree of ring formation indicates the degree to which the adjacent polycyclic aromatic and/or oligophenylene aromatic groups are fused together by dehydrocyclization. As will be more detailed below It is stated that if complete dehydrocyclization occurs in a specific region of the graphene nanobelt, the region will appear as a segment with the greatest degree of ring formation, and the neighboring segment is preferred because of partial dehydrocyclization in the region. A lower degree of looping.

In the present invention, it is possible that repeating units of different graphene fragments are derived from the same substituted or unsubstituted polycyclic aromatic monomer compound and/or oligophenylene aromatic hydrocarbon monomer compound, but the aromatic ring is formed. The degree of ring (ie, the degree of dehydrocyclization) is different. Since the degree of dehydrocyclization of the different graphene fragments is different, preferably, the widths of the fragments are also different.

In the present invention, it is also possible to have different repeating units and thus different fragments having the same degree of loop formation (for example, the fragments are completely dehydrocyclized), but the fragment widths are different. This can be achieved by using different polycyclic aromatic monomer compounds and/or oligophenylene aromatic hydrocarbon monomer compounds, or by condensing two precursor graphene nanoribbons on localized regions (eg Achieved by presenting a higher width segment in the final segmented graphene nanoribbon via a neighboring aromatic ring that is oriented at least partially parallel to each other in the adjacent graphene nanoribbon), as will be explained in more detail below .

In the present invention, the substituents to which the repeating units of different fragments are linked may be different, but the degree of dehydrocyclization may be the same or may be different. This can be achieved by using a polycyclic aromatic monomer compound having a different substituent attached to the (other) aromatic ring and/or an oligophenylene aromatic hydrocarbon monomer compound.

Preferably, the segments of the segmented graphene nanoribbons each have a length of from 0.25 to 250 nm, more preferably from 1 to 50 nm, and/or the total length of the segmented graphene nanoribbons is preferably at least 4 nm. , better at least 20 nm and can be as high as 1000 nm, more preferably up to 300 nm. Scanning tunneling microscopy (STM) was used to determine fragment length and graphene nanobelt length.

In a preferred embodiment, all segments of the segmented graphene nanoribbon are linearly arranged.

To provide such a linear configuration, each segment of the segmented graphene nanoribbon can be covalently bonded to up to two neighboring segments.

In the present invention, at least one fragment of the segmented graphene nanoribbon is also covalently bonded to at least three adjacent segments. The illustrative embodiments are described in more detail below, see, for example, the structure shown in Formula XI.

In a preferred embodiment, the two or more different segments have repeating units derived from a substituted or unsubstituted oxime monomer compound.

Preferably, the graphene nanoribbon comprising a segment of two or more segments of graphene having fluorene-based repeating units has the following structural formula Ia: The constraint is at least two of m, x, n, y, o, z, and p 1, and m+x+n+y+o+z+p 10, better, 2500 m+x+n+y+o+z+p 50, and wherein: X is independently H, halogen, SH, SR ₃ , OH, OR ₃ , OSO ₂ R ₃ , (SO) R ₃ , (SO ₂ ) R ₃ , NR ₁ R ₂ , NO ₂ , POR ₃ R ₃ , PO(OR ₃ )R ₃ , PO(OR ₃ ) ₂ , B(R ₃ ) ₂ , B(OR ₃ ) ₂ , (CO)R ₃ , (CO)OR ₃ , preferably H Or halogen, more preferably H; Y independently of each other is H or a direct bond between two adjacent Y repeating units; R is independently hydrogen; unsubstituted or via one or more OH, C ₁ -C _a linear or branched or cyclic C ₁ -C ₁₂ alkyl group substituted with alkoxy, phenyl or CN; a C ₂ -C ₁₂ alkyl group having one or more discontinuous O; halogen; OH; OR ₃ ; SR ₃ ; CN; NO ₂ ; NR ₁ R ₂ ; (CO) R ₃ ; (CO)OR ₃ ; O(CO)OR ₃ ; O(CO)NR ₁ R ₂ ; O(CO)R ₃ ; ₁ -C ₁₂ alkoxy; C ₁ -C ₁₂ alkylthio; (C ₁ -C ₆ alkyl)-NR ₇ R ₈ ; or -O-(C ₁ -C ₆ alkyl)NR ₁ R ₂ ; Aryl or heteroaryl (wherein the aryl group is preferably phenyl, biphenyl, naphthyl or anthracenyl, all of which are unsubstituted or via one or more C ₁ -C ₄ -alkyl, CN, _{oR 3, SR 3, CH 2} oR 3, substituted _{(CO) oR 3, (CO} ) NR 1 R 2 or halogen); or two R attached thereto, etc. Carbon atoms together form a 5-8 or heterocyclic ring; R ₁ and R ₂ are each independently hydrogen, a linear or branched C ₁ -C ₆ alkyl or phenyl, or R ₁ and R ₂ are bonded thereto other The nitrogen atoms of the junction together form a group selected from the group consisting of: , or ; R ₃ is H, C ₁ -C ₁₂ alkyl, unsubstituted or via one or more C ₁ -C ₄ alkyl, phenyl, halogen, C ₁ -C ₄ alkoxy or C ₁ -C ₄ Alkylthio substituted phenyl.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, the graphene nanoribbon comprising segments having two or more segments of the ruthenium-based repeating unit has the following structural formula Ib: The constraint is at least two of x, n, y, o, z, and p 1, and x+n+y+o+z+p 10, better, 2500 x+n+y+o+z+p 50, and wherein: X, Y and R are the same as defined above for formula Ia.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, the graphene nanoribbon comprising segments having two or more segments of the fluorene-based repeating unit has the following structural formula Ic: The constraint is at least two of y, o, z, and p 1, and y+o+z+p 10, better, 2500 y+o+z+p 50, and wherein: X, Y and R are as defined above for formula Ia.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, the graphene nanoribbon comprising a segment having two or more segments of the hydrazine-based repeating unit has the following structural formula Id: The constraint is at least two of m, x and n 1, and m+x+n 10, better, 2500 m+x+n 50, and wherein: X and R are as defined above for formula Ia.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, the graphene nanoribbon comprising segments having two or more segments of the hydrazine-based repeating unit has the following structural formula Ie: The constraint is at least two of m, z and p 1, where m+z+p 10, better, 2500 m+z+p 50, and wherein: X and R are as defined above for formula Ia.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, the graphene nanoribbon comprising segments having two or more segments of the fluorene-based repeating unit has the following structural formula Ih: Of which: m+n 10, better, 2500 m+n 50, and wherein: R1 and R2 are the same as R defined above under the different conditions of R1 and R2, and X is the same as defined above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

The two or more different graphene fragments may also have repeating units derived from a substituted or unsubstituted pentacene monomer compound.

In a preferred embodiment, the graphene nanoribbon comprising segments having two or more different segments of repeating units derived from a pentacene monomer compound has the following structural formula II: The constraint is at least two of m, x, n, y, o, z, and p 1, and m+x+n+y+o+z+p 10, better, 2500 m+x+n+y+o+z+p 50, and wherein X, Y and R have the same meanings as defined above for formula Ia.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

According to another preferred embodiment, the graphene nanoribbon comprising segments having two or more different segments of repeating units derived from a pentacene monomer compound has the following structural formula III: Of which: m+n 10, better, 2500 m+n 50, and wherein: R1 and R2 are the same as R defined above under the different conditions of R1 and R2, and X is the same as defined above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In the present invention, it is also possible that the two or more different graphene fragments have repeating units derived from a substituted or unsubstituted anthracene and a substituted or unsubstituted pentacene monomer compound.

According to a preferred embodiment, the graphene nanoribbon comprising segments having two or more different segments of repeating units derived from hydrazine and pentacene monomer compounds has the following structural formula IV: Where: m+n 10, better, 2500 m+n 50, and wherein: R1 and R2 are the same as R defined above under the different conditions of R1 and R2, and X is the same as defined above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

The two or more different graphene fragments may also have repeating units derived from a substituted and/or unsubstituted naphthalene monomer compound.

In a preferred embodiment, the graphene nanoribbon comprising segments having two or more different segments of repeating units derived from a naphthalene monomer compound has the following structural formula V: The constraint is at least two of m, x and n 1, and m+x+n 10, better, 2500 m+x+n 50, and wherein X, Y and R have the same meaning as indicated above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, a graphene nanoribbon comprising a segment having two or more different segments of a repeating unit derived from a naphthalene monomer compound has the following structural formula VI: The constraint is at least two of m, x and n 1, and m+x+n 10, better, 2500 m+x+n 35, and wherein X, Y and R have the same meaning as indicated above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, the graphene nanoribbon comprising segments having two or more different segments of repeating units derived from a naphthalene monomer compound has the following structural formula VII: The constraint is at least two of m, x and n 1, and m+x+n 10, better, 2500 m+x+n 30, and wherein X, Y and R have the same meaning as indicated above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, the graphene nanoribbon comprising a segment having two or more different segments of repeating units derived from a naphthalene monomer compound has the following structural formula VIII: The constraint is at least two of m, x and n 1, and m+x+n 10, better, 2500 m+x+n 25, and wherein X, Y and R have the same meaning as indicated above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, the graphene nanoribbon comprising segments having two or more different segments of repeating units derived from a naphthalene monomer compound has the following structural formula IX: The constraint is at least two of m, x and n 1, and m+x+n 10, better, 2500 m+x+n 30, and wherein X, Y and R have the same meaning as indicated above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, the graphene nanoribbon comprising a segment having two or more different segments of repeating units derived from a naphthalene monomer compound has the following structural formula X: The constraint is at least two of m, x and n 1, and m+x+n 10, better, 2500 m+x+n 20, and wherein X, Y and R have the same meaning as indicated above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, the graphene nanoribbon comprising segments having two or more different segments of repeating units derived from a naphthalene monomer compound has the following structural formula XIII: Of which: m+n 10, better, 2500 m+n 50, and wherein: R1 and R2 are the same as R as defined above under the constraints of R1 and R2, and X is as defined above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In the present invention, it is possible that at least one of the graphene fragments has a substituted or unsubstituted repeating unit having N1 dimer lines across a fragment width, and at least one of the graphene fragments The cross-fragment width has repeating units containing N2 dimer lines, wherein N1=5 to 13 (more preferably, N1=5, 7 or 11), and N2=k×N1, and k=2, 3 or 4 (more preferably 2 or 3).

In a preferred embodiment, the segmented graphene nanobelt comprises at least one segment having a repeating unit of N1=5 and at least one segment having N2=10,15 Or a fragment of a repeating unit of 20 (wherein N1 and N2 are counts of dimeric lines across the width of the fragment).

Preferably, comprising at least one segment of a substituted or unsubstituted repeating unit having N1=5 and at least one segment of a fragment having a substituted or unsubstituted repeating unit of N2=10 and/or N2=15 The graphene nanobelt has the chemical structure XI shown below: The constraint is at least one of at least one of m, p, q, r, s, u, v, w, and x, or at least three 1, and at least one of n, o, and t 1, and m+n+o+p+q+r+s+t+u+v+w+x 10, better, 2500 m+n+o+p+q+r+s+t+u+v+w+x 25, and wherein X and Y have the same meaning as indicated above.

Preferably, at least one of n, o and t 1, and at least two of m, p, q, r, s, u, v, w, and x 1. At least one of the graphene fragments is covalently bonded to two or more of the neighboring fragments.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In another preferred embodiment, comprising at least one segment of a segment having substituted or unsubstituted repeating units of N1=5 and at least one segment of graphite having a segment of substituted or unsubstituted repeating units having N2=10 The olefinic band has the chemical structure XII shown below: The constraint is at least one of at least two, or at least three, or even all of p, m, q, and o 1; and m+n+o+p+q 10, better, 2500 m+n+o+p+q 25, and wherein X and Y have the same meaning as indicated above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

According to another preferred embodiment, the segmented graphene nanobelt comprises at least a fragment of a substituted or unsubstituted repeating unit having N1=7 and at least one fragment having a substituted or unsubstituted repeating unit of N2=14 and/or 21.

In a preferred embodiment, the method comprises at least one segment of a substituted or unsubstituted repeating unit having N1=7 and at least one segment of a substituted or unsubstituted repeating unit having N2=14 and/or 21 The graphene nanobelt of the segment has the chemical structural formula If shown below.

The constraint is at least one of at least one of m, p, q, w, x, r, s, u, and v, or at least three 1, and at least one of n, o, and t 1, and m+n+o+p+q+r+s+t+u+v+w+x 10, better, 2500 m+n+o+p+q+r+s+t+u+v+w+x 25, and X and Y have the same meaning as indicated above.

Preferably, at least one of n, o and t 1, and at least two of m, p, q, r, s, u, v, w, and x 1. At least one of the graphene fragments is covalently bonded to two or more of the adjacent graphene fragments.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

In a preferred embodiment, comprising at least one segment of a substituted or unsubstituted repeating unit having N1=7 and at least one segment of graphene having a segment of a substituted or unsubstituted repeating unit having N2=14 The nanobelt has the chemical structural formula Ig shown below.

The constraint is at least one of m, p, q, and o, at least two or at least three, or even all 1, where m+n+o+p+q+r+s+t+u+v+w+x 10, better, 2500 m+n+o+p+q+r+s+t+u+v+w+x 25, wherein X and Y have the same meaning as indicated above.

As indicated above, a is preferably from 1 to 50. More preferably, a is from 1 to 10, and more preferably from 1 to 5. If 2 a l (where l is preferably 50, more preferably 10, still more preferably 5, as indicated above), the segmented graphene nanoribbon includes 1 structural part a ₁ , a ₂ , ... ., a _l .

Preferably, the segmented graphene nanobelt comprises at least one heterojunction.

The heterojunction occurs at the interface of two covalently bonded graphene fragments having different electronic properties (eg, different energy band gaps).

According to another aspect, the present invention provides a method for producing a segmented graphene nanoribbon as defined above, the method comprising: (a) at least one polycyclic aromatic monomer compound and/or oligobenzene a base aromatic hydrocarbon monomer compound deposited on a solid substrate, (b) polymerizing a polycyclic aromatic and/or oligophenylene aromatic hydrocarbon monomer compound to form at least one polymer on the surface of the solid substrate Preferably, the at least one polymer is linear, (c) at least partially dehydrocycling the one or more polymers of step (b).

The polycyclic aromatic monomer (preferably, a polycyclic aromatic hydrocarbon monomer compound) and/or the oligophenylene aromatic hydrocarbon monomer compound of the step (a) may be subjected to polymerization to polymerization under suitable reaction conditions. Any compound of the material (preferably a linear polymer). The polycyclic aromatic monomer or oligophenylene aromatic hydrocarbon monomer compound which can react to form a polymer is generally known to those skilled in the art.

Preferably, the polycyclic aromatic monomer and/or oligophenylene aromatic hydrocarbon monomer compound is substituted with at least two leaving groups, more preferably at least two halogens, preferably Br and/or I. Base, which provides a reaction site for subsequent polymerization.

The polycyclic aromatic monomer compound may, for example, be a compound such as those of the formula 1-3 shown below, such as the formula 4 shown below. A diterpene-based compound, or a compound based on a triterpenoid such as those shown in Formula 5 below. A variety of such compounds are commercially available or can be made by those skilled in the art in light of the literature. Reference may also be made to the polycyclic aromatic monomer compounds which have been described above in connection with the compounds of the graphene fragment repeating unit source.

In Formulas 1 to 5, preferably, X is independently of each other a leaving group, preferably Br or I; R is independently hydrogen; unsubstituted or via one or more OH, C ₁ -C ₄ alkane a linear or branched or cyclic C ₁ -C ₁₂ alkyl group substituted with an oxy group, a phenyl group or a CN; a C ₂ -C ₁₂ alkyl group having one or more discontinuous O; halogen; OH; OR ₃ ; ₃ ;CN;NO ₂ ;NR ₁ R ₂ ;(CO)R ₃ ;(CO)OR ₃ ;O(CO)OR ₃ ;O(CO)NR ₁ R ₂ ;O(CO)R ₃ ;C ₁ - C ₁₂ alkoxy; C ₁ -C ₁₂ alkylthio; (C ₁ -C ₆ alkyl)-NR ₇ R ₈ ; or -O-(C ₁ -C ₆ alkyl)NR ₁ R ₂ ; aryl Or a heteroaryl group (wherein the aryl group is preferably a phenyl group, a biphenyl group, a naphthyl group or a fluorenyl group, which are all unsubstituted or one or more C ₁ -C ₄ -alkyl groups, CN, OR ₃ , SR ₃ , CH ₂ OR ₃ , (CO)OR ₃ , (CO)NR ₁ R ₂ or halogen substitution); or two R and its attached carbon atom together form a 5 to 8 membered ring or heterocyclic ring; R ₁ And R ₂ are independently of each other hydrogen, a linear or branched C ₁ -C ₆ alkyl group or a phenyl group, or R ₁ and R ₂ are bonded together with a nitrogen atom to which they are bonded, and are selected from the group consisting of , or a group; R ₃ is H, C ₁ -C ₁₂ alkyl, unsubstituted or via one or more C ₁ -C ₄ alkyl, phenyl, halogen, C ₁ -C ₄ alkoxy or C ₁ -C ₄ alkylthio substituted phenyl.

The monomeric compound may also be a pentacene-based compound such as a compound of formulas 6 and 7. This type of compound can be made by a person skilled in the art in accordance with a literature procedure.

X and R have the same meaning as defined above for Formulas 1 to 5.

The monomeric compound may also be a phenanthrene-based compound such as a compound of formulas 8 and 9 . Monomers of this type are described, for example, in US 7,968,872.

X and R have the same meaning as defined above for Formulas 1 to 5.

The monomeric compound may also be an oligophenylene aromatic hydrocarbon compound such as described in, for example, patent application EP 11 186 716.4 and EP 11 186 659.6, such as compounds 100 to 104 shown below.

Wherein: X and R have the same meaning as defined above for Formulas 1 to 5.

Wherein: R1, R2 and R3 which may be the same or different are H, halogen, -OH, -NH ₂ , -CN, -NO ₂ , linear or branched saturated or unsaturated C ₁ -C ₄₀ hydrocarbon residue , which may be substituted 1- to 5-fold by halogen (F, Cl, Br, I), -OH, -NH ₂ , -CN and/or -NO ₂ , and one or more of the CH ₂ - groups may be Substituted by -O-, -S-, -C(O)O-, -OC(O)-, -C(O)-, -NH- or -NR-, wherein R is optionally substituted C ₁ a -C ₄₀ hydrocarbon residue, or an optionally substituted aryl, alkylaryl or alkoxyaryl residue, and X is a halogen.

Wherein: R1, R2 and R3 which may be the same or different are H, halogen, -OH, -NH ₂ , -CN, -NO ₂ , linear or branched saturated or unsaturated C ₁ -C ₄₀ hydrocarbon residue, It may be substituted 1- to 5-fold by halogen (F, Cl, Br, I), -OH, -NH ₂ , -CN and/or -NO ₂ , and one or more of the CH ₂ - groups may be -O-, -S-, -C(O)O-, -OC(O)-, -C(O)-, -NH- or -NR-substitution, wherein R is optionally substituted C ₁ - a C ₄₀ hydrocarbon residue or an optionally substituted aryl, alkylaryl or alkoxyaryl residue, X is a halogen and Y is H, or X is H and Y is a halogen.

The monomeric compound may also be a compound based on naphthacene, such as those of formulas 10 to 13. This type of compound can be made by a person skilled in the art in accordance with a literature procedure.

Wherein: X and R have the same meaning as defined above for Formulas 1 to 5.

The monomeric compound may also be a naphthalene based compound such as those of formulas 14 to 22. This type of compound can be made by a person skilled in the art in accordance with a literature procedure.

Wherein: X and R have the same meaning as defined above for Formulas 1 to 5.

As indicated above, step (a) comprises depositing at least one polycyclic aromatic monomer or oligophenylene aromatic hydrocarbon monomer compound on a solid substrate.

Any solid substrate on which a polycyclic aromatic monomer or an oligophenylene aromatic hydrocarbon monomer compound can be deposited and subsequently polymerized into a linear polymer can be used. Preferably, the solid substrate has a flat surface.

The flat surface deposited by the monomeric compound may be a metal surface such as Au, Ag, Cu, Al, W, Ni, Pt or Pd surface (which may be reconstructed or adjacent), or the surface may be such a metal alloy. The surface can be completely flat or patterned or ladder shaped. Such patterned or laddered surfaces and methods of making same are known to those skilled in the art. On the patterned surface, the growth of the graphene nanoribbons can be guided by a surface pattern.

The surface may also be a metal such as cerium oxide, cerium oxynitride, cerium lanthanum hydride, cerium nitride (HfSiON), zirconium silicate, cerium oxide and zirconium dioxide, or aluminum oxide, copper oxide or iron oxide. Oxide surface.

The surface can also be made of a semiconductor material such as tantalum, niobium, gallium arsenide, tantalum carbide, and molybdenum disulfide.

The surface can also be a material such as boron nitride, sodium chloride or calcite.

The surface can be electrically conductive, semiconductor specific or insulative.

Deposition on the surface can be accomplished by any method suitable for depositing organic compounds on the surface. The method can be, for example, a vacuum deposition (sublimation) method, a solution-based method such as spin coating, spray coating, dip coating, printing, or a laser-induced desorption method.

Preferably, the deposit is accomplished by vacuum deposition. Preferably, it is a vacuum sublimation method. The vacuum can range from 10 ^-3 to 10 ^-11 mbar.

As indicated above, step (b) of the process of the invention comprises polymerizing a polycyclic aromatic monomer and/or an oligophenylene aromatic hydrocarbon monomer compound to form at least one polymer on the surface of the solid substrate, at least one of which The polymer is preferably linear.

Suitable conditions for effecting polymerization of the polycyclic aromatic monomer and/or oligophenylene aromatic hydrocarbon monomer compound are generally known to those skilled in the art.

Preferably, the polymerization in step (b) is initiated by thermal activation. However, any other energy input, such as radiation, that initiates polymerization of the polycyclic aromatic monomer and/or oligophenylene aromatic hydrocarbon monomer compound can also be used.

The activation temperature depends on the surface and monomer used and can range from 0 to 500 °C.

Optionally, step (a) and/or step (b) may be repeated at least once prior to performing partial or complete dehydrocyclization in step (c). When repeating steps (a) and (b), the same monomeric compound or different polycyclic aromatic monomer and/or oligophenylene aromatic hydrocarbon monomer compound may be used.

As indicated above, step (c) of the process of the invention comprises at least partially dehydrocyclizing the one or more polymers of step (b).

In general, suitable reaction conditions for dehydrocyclization are known to those skilled in the art.

In a preferred embodiment, the polymer of step (b) is subjected to partial dehydrocyclization.

According to the preferred embodiment, the reaction conditions are selected to avoid complete dehydrocyclization. If complete dehydrocyclization occurs, each polycyclic aromatic repeat unit will be fully looped to its nearest neighbor. However, in step (b), the partial dehydrogenation of the polymer A fragment of the final graphene nanoribbon band having a different degree of ringing between adjacent units. Each fragment in the segmented graphene nanoribbon has a degree of ringing between its particular adjacent polycyclic aromatic repeating units. Therefore, by using a partial dehydrocyclization step, even if only one polycyclic aromatic monomer or oligophenylene aromatic hydrocarbon monomer compound is deposited on a solid substrate in the step (a), a segmentation can be obtained. Graphene nanobelt.

Preferably, the partial dehydrocyclization reaction is initiated by thermal activation. The activation temperature is preferably higher than the temperature in the first activation step initiating the polymerization. The activation temperature for partial dehydrocyclization depends on the surface used and the polymer precursor and may range from 50 to 600 °C.

In order to obtain a segmented graphene nanobelt, it is preferred to select an activation temperature and an activation time to avoid completion of the dehydrocyclization reaction to obtain a non-segmented graphene nanobelt.

For example, in the case of a precursor polymer derived from a compound of the type 2 dibromo-diindenyl type on the gold surface, partial desorption can be achieved by maintaining the temperature at about 327 ° C (600 K) for about 5 minutes. Hydrocyclization. If, for example, the same dehydrocyclization on gold is carried out at 397 ° C (670 K) for 10 minutes, complete dehydrocyclization is achieved.

According to another preferred embodiment of the present invention, at least two polymers of step (b) are subjected to complete dehydrocyclization to form first and second precursor graphene nanoribbons, followed by the first precursor At least one repeating unit of the graphene nanoribbon is looped to at least one repeating unit of the second precursor graphene nanoribbon to form a segmented graphene nanobelt.

The two precursor graphene nanoribbons have been fused together in the region where they are The graphene nanoribbons in the final segment are graphene fragments having a higher fragment width than the neighboring segments.

For example, on the gold surface, the ringing of the two adjacent precursor graphene nanoribbons can be carried out by maintaining the temperature at about 437 ° C (710 K) for about 5 minutes.

In a preferred embodiment, at least two different polycyclic aromatic monomers or oligophenylene aromatic hydrocarbon monomer compounds are deposited on the solid substrate in step (a).

According to the preferred embodiment, preferably two or more different monomeric compounds having similar reactivity are deposited on the surface of the solid substrate, followed by initiation of polymerization to form a copolymer (preferably a linear copolymer). Subsequently, a partial or complete dehydrocyclization reaction is carried out to obtain a segmented graphene nanobelt.

In a variation of the preferred embodiment, the first polycyclic aromatic monomer or oligophenylene aromatic hydrocarbon monomer compound is deposited on the surface of the solid substrate, followed by initiation of polymerization to form a polymer (preferably Is a linear polymer). The second monomer is then deposited on the same substrate surface, followed by initiation of polymerization to form a block copolymer (preferably a linear block copolymer). This step can be repeated several times using the same or using different monomer compounds as needed to obtain a multi-block copolymer. Subsequently, the block copolymer is subjected to a partial or complete dehydrocyclization reaction to obtain a segmented graphene nanobelt.

In a preferred embodiment, the partial or complete dehydrocyclization reaction is initiated by a spatially controlled external stimulus.

The external stimulus can generally be current, heat, ion beam, oxidative plasma, microwave, light or electromagnetic radiation or it can be an oxidizing chemical. The spatial control of activation can be accomplished using a highly focused activation stimulus that controls the position of the substrate. The space-limited activation stimulus can be derived, for example, from a tunneling microscope The tip-sized nano-sized electrode is derived from highly focused electromagnetic radiation such as, for example, a focused laser beam or from a highly focused electron beam such as in an electron microscope. Spatial control of activity can also be achieved using, for example, a nanostructured mask of a reticle to direct the effects of activation stimuli.

The resulting segmented graphene nanoribbons can be used directly on the substrates on which they are made or they can be transferred to another substrate.

Instance 1. Experimental details

The molecular precursor 10,10'-dibromo-9,9'-didecyl group is sublimed at a rate of 1 Å/min for 100 seconds to clean Au (111) by argon ion bombardment and annealing to 750 K. On a single crystal substrate. The substrate was maintained at room temperature during deposition and then annealed to 480 K immediately to initiate dehalogenation and free radical addition. The sample was then annealed at 600 K for 5 min to partially dehydrogenate the polymer.

Example 1: Preparation of segmented graphene nanoribbons from a molecular precursor 10,10'-dibromo-9,9'-didecyl group by thermally activated dehydrocyclization

The main step in the bottom-up GNR manufacturing process is the surface-assisted thermal initiation of dehydrocyclization of linear poly-phenylenes on Au or Ag-like plates. The method of not requiring Lewis acid or other catalysts other than supporting the metal substrate is highly selective and effective. Scanning tunneling microscopy (STM) experiments show that the polyfluorene chain adsorbed on the Au or Ag substrate undergoes dehydrocyclization immediately upon annealing at 670 K: alternating "up" and "down" pointing thiol units The ends are coupled to each other and the buckling polymer chain is converted to a fully planar 7-AGNR (with The hand chair type configuration and the cross-section width have a graphene nanobelt of 7 dimer lines).

Figures 1a and 1b illustrate the formation of a graphene nanoribbon heterojunction by partial dehydrocyclization of the polyfluorene oligomer. Figure 1a shows an STM measurement and corresponding atomic model demonstrating the synthesis of AGNR starting from a polyfluorene chain assembled on an Au(111) substrate. The deposition of the molecular precursor on the substrate maintained at 470 K promotes dehalogenation and intermolecular binding of the monomer via the surface of the resulting diradical intermediate to produce a polyfluorene oligomer (left). Annealing at 670 K triggers dehydrocyclization of 7-AGNR (right). Annealing at a reduced temperature of 600 K for 5 minutes results in partial dehydrocyclization and an in-band heterojunction as shown in Figure 1b. The STM image and the corresponding atomic model show an atomic-level exact junction between a fully reactive N=7 AGNR with a width w7=0.74 nm and a partial reaction polyfluorene fragment (N=5+) with a width w5+=0.49 nm. The STM image is obtained in a constant current mode at 35 K (V bias = 1 V I = 0.1 nA).

Example 2: Dehydrocyclization initiated by STM tip to produce segmented graphene nanoribbons from molecular precursor 10,10'-dibromo-9,9'-didecyl

Dehydrocyclization is caused by an electronic injection trigger from the tip of the STM. Starting from the heterojunction obtained by medium annealing as described in Example 1, the length of the 5+-AGNR region was shortened by the use of a voltage pulse applied to the tip of the STM to control dehydrocyclization with the aid of the 7-AGNR fragment. .

Figures 2a-c illustrate an example of a 7-GNR having a 5+-AGNR region, wherein the 5+-AGNR region is shortened by one unit by electron activated dehydrogenation. Figure 2a (top left) shows the STM image and corresponding atomic model of the N=7/5+/7 heterojunction obtained by thermally controlled annealing. Figure 2b (bottom left) shows the front heterojunction at the tip STM image and corresponding atomic model after deriving an extra unit of dehydrogenation. The circular mark in Figure 2a is the position of the lateral tip during the electron activation dehydrogenation process. Figure 2c (right) shows the I-V curve showing the activation reaction at -2.5V.

Figure 3 is a schematic diagram showing the STM topography of an example of a heterostructure formed by partial dehydrocyclization of a polyfluorene oligomer at 600 K (V bias = -2 V, I = 0.02 nA). Figure 3a shows two N=7 bands containing N=5+ fragments. Figure 3b shows a heterostructure consisting of N=7 AGNR and polyfluorene oligomer fragments. Figure 3c shows a N=5+AGNR/polyfluorene oligomer heterostructure.

Figure 4 is a schematic diagram showing the STM shape of a heterojunction having three different segments formed by partial dehydrocyclization of a polyfluorene oligomer at 600 K (V bias = -2 V, I = 0.02 nA). Look at the picture. The fragments are polyfluorene oligomers, N = 5 + AGNR and N = 7 AGNR.

Example 3: Fabrication of segmented graphene nanoribbons by thermally annealing non-segmented graphene nanoribbons

The AGNR was prepared starting from the assembled polyfluorene chain on the Au (111) substrate. The deposition of the molecular precursor on the substrate maintained at 470 K promotes dehalogenation and intermolecular binding of the monomer via the surface of the resulting diradical intermediate to produce a polyfluorene oligomer. Annealing at 670 K triggers dehydrocyclization of the non-segmented 7-AGNR. Annealing at 710 K for 5 minutes resulted in segmented graphene nanoribbons due to thermal ring formation of the non-segmented tape.

Figure 5 is a schematic diagram showing the STM topography of a heterojunction formed by treatment of a polyfluorene oligomer after annealing at 710 K (V bias = -0.5 V, I = 0.1 nA). Dehydrogenation edge coupling between individual N=7 AGNRs is triggered at this temperature to form N=14 in N=7 AGNR (width w7=0.74 nm) AGNR fragment (width w14 = 1.60 nm).

Figures 1a and 1b illustrate the formation of a graphene nanoribbon heterojunction by partial dehydrocyclization of a polyfluorene oligomer.

Figures 2a-c illustrate an example of a 7-GNR having a 5+-AGNR region wherein the 5+-AGNR region is shortened by one unit by electron activation dehydrogenation.

Figure 3 is a diagram showing the STM topography of an example of a heterostructure formed by partial dehydrogenation of a polyfluorene oligomer at 600 K (V bias = -2 V, I = 0.02 nA).

Figure 4 is a schematic diagram showing a heterojunction having three different segments formed by partial dehydrocyclization of a polyfluorene oligomer at 600 K (V bias = -2 V, I = 0.02 nA). STM topography.

Figure 5 is a schematic diagram showing the STM topography of a heterojunction formed by treatment of a polyfluorene oligomer after annealing at 710 K (V bias = -0.5 V, I = 0.1 nA).

Claims (21)

A segmented graphene nanoribbon comprising at least two different graphene segments covalently bonded to each other, each graphene segment having a monodisperse fragment width, wherein at least one of the graphene fragments The width is 4 nm or less. A graphene nanoribbon strip as claimed in claim 1, wherein each graphene fragment of the segmented graphene nanoribbon has a monodisperse fragment width of 4 nm or less. A graphene nanobelt according to claim 1 or 2, wherein each graphene segment has a repeating unit derived from at least one substituted or unsubstituted polycyclic aromatic monomer compound, more preferably Derivatized from at least one substituted or unsubstituted polycyclic aromatic hydrocarbon monomer compound, and/or derived from at least one substituted or unsubstituted phenylene aromatic hydrocarbon monomer compound. A graphene nanoribbon strip as claimed in claim 1 or 2, wherein the repeating units of different graphene fragments differ in at least one or more of the following characteristics selected from the group consisting of a fragment width, linked to the repeat The substituent of the unit, the degree of ring formation of the aromatic ring or the degree of dehydrocyclization and/or the number of ring-forming aromatic rings. A graphene nanobelt according to claim 1 or 2, wherein each segment of the segmented graphene nanoribbon has a length of from 0.25 to 250 nm, and/or the segmented graphene nanoribbon The total length is at least 4 nm. A graphene nanobelt according to claim 1 or 2, wherein the segments of the segmented graphene nanoribbon are linearly arranged, or the segmented graphite At least one fragment of the olefinic band is covalently bonded to at least three adjacent segments. The graphene nanoribbon of claim 1 or 2, wherein at least one of the graphene fragments has a substituted or unsubstituted repeating unit having N1 dimer lines across a fragment width, and At least one of the equal graphene fragments has a substituted or unsubstituted repeating unit having N2 dimeric lines across the width of the fragment, wherein N1 = 5 to 13, and N2 = k x N1, and k = 2, 3 Or 4. The graphene nanoribbon of claim 1 or 2, wherein the two or more different graphene fragments have repeating units derived from a substituted or unsubstituted fluorene monomer compound, the segmented graphite The olefinic band preferably has the following structural formula Ia: The constraint is at least two of m, x, n, y, o, z, and p 1, and m+x+n+y+o+z+p 10, and wherein: X is independently H, halogen, SH, SR ₃ , OH, OR ₃ , OSO ₂ R ₃ , (SO) R ₃ , (SO ₂ ) R ₃ , NR ₁ R ₂ , NO ₂ , POR ₃ R ₃ , PO(OR ₃ )R ₃ , PO(OR ₃ ) ₂ , B(R ₃ ) ₂ , B(OR ₃ ) ₂ , (CO)R ₃ , (CO)OR ₃ , preferably H Or halogen, more preferably H; Y independently of each other H or two Ys between adjacent repeating units form a direct bond; R is independently hydrogen; unsubstituted or via one or more OH, C ₁ a linear or branched or cyclic C ₁ -C ₁₂ alkyl group substituted with a C ₄ alkoxy group, a phenyl group or a CN; a C ₂ -C ₁₂ alkyl group having one or more discontinuous O; a halogen; OH; OR ₃ ; SR ₃ ; CN; NO ₂ ; NR ₁ R ₂ ; (CO) R ₃ ; (CO)OR ₃ ; O(CO)OR ₃ ; O(CO)NR ₁ R ₂ ; O(CO)R ₃ ; C ₁ -C ₁₂ alkoxy; C ₁ -C ₁₂ alkylthio; (C ₁ -C ₆ alkyl)-NR ₇ R ₈ ; or -O-(C ₁ -C ₆ alkyl)NR ₁ R _An aryl or heteroaryl group (wherein the aryl group is preferably a phenyl group, a biphenyl group, a naphthyl group or a fluorenyl group, which are all unsubstituted or one or more C ₁ -C ₄ -alkyl groups, _{CN, oR 3, SR 3,} CH 2 oR 3, substituted _{(CO) oR 3, (CO} ) NR 1 R 2 or halogen); or two R with their Is connected to carbon atom together form a 5-8 or heterocyclic ring; R ₁ and R ₂ are each independently hydrogen, a linear or branched C ₁ -C ₆ alkyl or phenyl, or R ₁ and R ₂ with each other The nitrogen atoms bonded together are selected from , or a group; R ₃ is H, C ₁ -C ₁₂ alkyl, unsubstituted or via one or more C ₁ -C ₄ alkyl, phenyl, halogen, C ₁ -C ₄ alkoxy or C ₁ -C ₄ alkylthio substituted phenyl. The graphene nanoribbon of claim 1 or 2, wherein the two or more different graphene fragments have repeating units derived from a substituted or unsubstituted pentacene monomer compound, The segmented graphene nanoribbon preferably has the following structural formula II: The constraint is at least two of m, x, n, y, o, z, and p 1, where m+x+n+y+o+z+p 10, and X, Y and R thereof have the same meaning as defined in claim 8. The graphene nanoribbon of claim 1 or 2, wherein the two or more different graphene fragments have repeating units derived from substituted or unsubstituted anthracene and pentacene monomer compounds The segmented graphene nanoribbon preferably has the following structural formula IV: Where m+n 10, and R1 and R2 thereof are the same as R defined in claim 8, but the constraint is that R1 is different from R2, and X is the same as defined in claim 8. The graphene nanoribbon of claim 1 or 2, wherein the two or more different graphene fragments have repeating units derived from a substituted and/or unsubstituted naphthalene monomer compound, The segmented graphene nanoribbon preferably has the following structural formula V: The constraint is at least two of m, x and n 1, where m+x+n 10, and X, Y and R thereof have the same meaning as in claim 8. The graphene nanoribbon of claim 1 or 2, wherein at least one of the fragments has a substituted or unsubstituted repeating unit of N1=5 and at least one of the fragments has N2 a substituted or unsubstituted repeating unit of 10 or 15 wherein N1 and N2 are the number of dimer lines across the width of the segment, and the segmented graphene nanoribbon preferably has the following chemical formula XI: The constraint is at least one of m, p, q, r, s, u, v, w, and x 1, and at least one of n, o, and t 1, where m+n+o+p+q+r+s+t+u+v+w+x 10, and X and Y thereof have the same meaning as in claim 8. The graphene nanoribbon of claim 1 or 2, wherein at least one of the fragments has a substituted or unsubstituted repeating unit of N1=7 and at least one of the fragments has N2 a substituted or unsubstituted repeating unit of 14 or 21 wherein N1 and N2 are the number of dimer lines across the width of the segment, and the segmented graphene nanoribbon preferably has the following chemical structural formula If: The constraint is at least one of m, p, q, w, x, r, s, u, and v 1, and at least one of n, o, and t 1, where m+n+o+p+q+r+s+t+u+v+w+x 10, and X and Y thereof have the same meaning as in claim 8. A graphene nanobelt of claim 1 or 2 comprising at least one heterojunction. A method for producing a segmented graphene nanobelt according to any one of claims 1 to 14, which comprises: (a) at least one polycyclic aromatic monomer compound and/or oligophenylene The aromatic hydrocarbon monomer compound is deposited on a solid substrate, (b) polymerizing the polycyclic aromatic and/or oligophenylene aromatic hydrocarbon monomer compound to form at least one polymer on the surface of the solid substrate The at least one polymer is preferably linear, (c) dehydrocyclizing the one or more polymers of step (b) at least in part. The method of claim 15, wherein the polymerization in step (b) is initiated by thermal activation. The method of claim 15 or 16, wherein the polymer of step (b) is subjected to partial dehydrocyclization. The method of claim 15 or 16, wherein the at least two polymers of step (b) are subjected to complete dehydrocyclization to form first and second precursor graphene nanoribbons, followed by the first precursor graphite At least one repeating unit of the olefinic strip is looped with at least one repeating unit of the second precursor graphene nanoribbon to form a segmented graphene nanobelt. The method of claim 15 or 16, wherein in step (a), at least two different polycyclic aromatic monomers or oligophenylene hydrocarbon monomer compounds are deposited on a solid substrate, followed by b) Polymerization to form a copolymer which is then at least partially dehydrocyclized in step (c). The method of claim 15 or 16, wherein: in step (a), the first polycyclic aromatic monomer or oligophenylene aromatic hydrocarbon monomer compound is deposited on a solid substrate, followed by step (b) Polymerization occurs to form a first polymer on the solid substrate, and repeating step (a) with a second polycyclic aromatic monomer or an oligophenylene aromatic hydrocarbon monomer compound different from the first monomer compound And (b) forming a block copolymer with the first polymer on the solid substrate, and repeating steps (a) and (b) at least once to provide a multi-block copolymer, The block copolymer is then at least partially dehydrocyclized in step (c). The method of claim 15 or 16, wherein the partial or complete dehydrocyclization is initiated by a spatially controlled external stimulus.